Integrated circuits are usually manufactured on semiconductor wafers which are subsequently cut into individual dies. Each die is a microelectronic device, such as a memory cell array, a processor, an electronic or opto-electronic sensor array, a micro-electromechanical system (MEMS), and the like. Such a device, which may be extremely thin, is mounted on a substrate which protects the mechanical integrity of the device and provides connectivity to other circuits of a microelectronic assembly. Complex devices may require many tens, even hundreds of input and output connections to the substrate.
In many applications (for example, digital cameras, cellular phones, laptop computers, or biometric devices such as finger print readers, among other applications), substrates carrying microelectronic devices are interconnected with other circuits using flexible cables. Conventionally, a flexible cable (e.g., tape cable) is connected to terminals of the substrate using a wire bonding or ball bonding technique. Together with the flexible cable, the substrate forms a two-component packaging platform for the device of the respective microelectronic assembly.
Despite considerable efforts devoted in the art heretofore to development of substrates for microelectronic assemblies and methods for fabricating such substrates, further improvement would be desirable.